JP2007250682A - Substrate processor, temperature control method thereof, and substrate processing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature control method of a substrate processor with which an appropriate setting temperature of a heating means, which achieves desired temperature distribution in a processing chamber, can uniquely be decided in short time irrespective of an operator, and to provide a substrate processing system and the substrate processor. <P>SOLUTION: A substrate processing is performed for making respective heaters to the prescribed setting temperature. A physical value which belongs to the substrate on which the substrate processing is performed, and which fluctuates in accordance with a processing temperature is acquired in measuring positions whose number is larger than the number of heaters. A deviation between the acquired physical value and a target value of the physical value is operated at every measuring position. A correction amount of the setting temperatures of the respective heaters is operated by using determinant based on the deviation in the respective measuring positions, and a change amount of the physical value in the respective measuring positions when one heater temperature is changed by 1°C. A subsequent substrate processing is performed by making a temperature obtained by adding a setting temperature correction amount to the prescribed setting temperature as a new setting temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate processing apparatus temperature control method, a substrate processing apparatus, and a substrate processing system mainly used in a semiconductor device manufacturing process, and more particularly to a substrate processing apparatus temperature control method for processing a substrate in a heated atmosphere, The present invention relates to a substrate processing apparatus and a substrate processing system.

  In the manufacturing process of a semiconductor device, a substrate processing apparatus for processing a semiconductor substrate in a heating atmosphere is frequently used in an oxidation process, a film forming process, a diffusion process, and the like. As this type of substrate processing apparatus, there is a batch type substrate processing apparatus in which a plurality of semiconductor substrates are accommodated in a processing chamber at a time for processing.

  For example, a low-pressure CVD (Chemical Vapor Deposition) system, which is a vertical batch-type substrate processing system, is a vertical (bell-shaped) process that accommodates a boat in which a plurality of wafers are placed at appropriate intervals in the vertical direction. A room is provided. The processing chamber is made of quartz or the like, and a plurality of annular heaters that can be controlled independently from each other are arranged along the vertical direction on the outer periphery of the processing chamber. In this type of apparatus, the temperature of each heater itself or the temperature between the heater and the processing chamber is measured as the heater temperature, and each heater is controlled to a state where the heater temperature becomes a preset temperature designated. Each heater is set to a temperature at which all wafers placed on the boat are in the same processing state, that is, the processing chamber has a uniform temperature distribution.

  However, when the set temperature of a specific heater is changed to a different temperature, not only the film formation rate of the space in the processing chamber (hereinafter referred to as the heating zone) in which the heater mainly heats, but also the formation of the heating zones of other heaters. The film rate also fluctuates (hereinafter, this phenomenon is referred to as an interaction between temperature and film formation rate as appropriate). For example, when the set temperature of a specific heater is increased, the film formation rate in the heating zone of the heater is increased. In this case, the film formation rate in the heating zone of the adjacent heater is slightly increased due to heat conduction. In the low pressure CVD apparatus, the source gas for the deposited film flows, for example, in a direction from the bottom to the top of the boat. As the deposition rate increases, more of the source gas is consumed. Therefore, if the set temperature of the upstream heater increases, the partial pressure of the source gas decreases in the heater heating zone located downstream of the source gas flow. The rate decreases. Therefore, in order to determine an appropriate set temperature for each heater, it is necessary to adjust the set temperature in consideration of the interaction between the temperature and the film formation rate as described above.

  Such determination of the set temperature of each heater is usually performed by performing a film formation test and measuring the film thickness of the film actually deposited on the wafer. In other words, the film formation conditions (film formation temperature and film formation time in each zone) are changed until the film thickness of the film actually deposited on the wafer becomes constant regardless of the mounting position on the boat. The film formation test is repeatedly performed. The number of film formation tests is reduced if the film thickness obtained by measurement is appropriately reflected in the heater temperature in consideration of the interaction between the temperature and the film formation rate. However, in order to appropriately reflect the measured film thickness, skill of an operator is required, and it is not an operation that can be easily performed by anyone. An inexperienced worker requires a lot of work time and reduces the operating rate of the apparatus.

  In addition, there is a substrate processing apparatus capable of controlling the set temperature of the heater in units of 0.1 ° C. in order to enable more precise temperature adjustment. However, in the above-described method, it is difficult for even a skilled worker to determine the set temperature of each heater in units of 0.1 ° C., so that the function is not utilized. In recent minute semiconductor devices, there are cases in which it is difficult to ensure the target film thickness uniformity under the condition where the temperature is not set in units of 0.1 ° C.

For this reason, various methods for determining the set temperature of each heater have been proposed. For example, in Patent Document 1 described later, first, film formation is performed on a plurality of monitoring wafers using existing process data, and an average film thickness of a film grown on each monitoring wafer is acquired. A film formation rate of the monitoring wafer whose average film thickness is closest to the target film thickness is obtained, and a film formation time for obtaining the target film thickness is calculated. In the calculated film formation time, the film thickness formed on another monitoring wafer is estimated. Next, based on the difference between the estimated film thickness and the target film thickness and the amount of change in film thickness per 1 ° C. at the mounting position of the other monitoring wafer, The temperature is determined. Under the conditions, the film thickness formed on the other monitoring wafer is estimated again using the film formation rate that takes into account the effect of temperature change. And the set temperature of the remaining heaters is calculated based on the difference between the estimated film thickness and the target film thickness and the amount of change in film thickness per 1 ° C. at the other monitoring wafer placement position. Thereby, the film thickness of the film formed on the wafers belonging to the same batch can be brought close to the target film thickness.
JP 2000-91251 A

  However, in the technique disclosed in Patent Document 1, the temperature of each heater is corrected after the film formation time is determined. For this reason, a change in film formation rate that occurs when temperature correction is performed cannot be reflected in the film formation time. When the heater temperature is increased, the film formation rate is increased, and when the heater temperature is decreased, the film formation rate is decreased. Therefore, the film formation rate differs before and after temperature correction. For this reason, if the temperature correction is performed after the film formation time is set, the film formation rate that is the calculation reference of the film formation time changes, and the film thicknesses of all the wafers belonging to the batch may deviate from the target film thickness.

  In the above prior art, a coefficient that takes into account the effect of temperature changes of other heaters is used when calculating the temperature correction value of each heater, but the temperature correction value of each heater is obtained independently. For this reason, the influence of the heater temperature whose temperature correction value has been calculated later cannot be reflected in the heater temperature whose temperature correction value has been previously calculated. That is, the temperature correction value for each heater is not optimized and the interaction between temperature and film formation rate is not accurately reflected. In recent years, with the miniaturization of the element pattern, the film thickness of the film constituting the element has become thinner, so that the batch processing equipment is required to have further uniformity. In order to realize such uniformity, it is indispensable to accurately reflect the interaction between the temperature and the film formation rate.

  On the other hand, from the viewpoint of reducing manufacturing variation, a single-wafer type substrate processing apparatus that processes wafers one by one in a processing chamber is used. Since the single-wafer substrate processing apparatus has a smaller processing chamber volume than the batch type substrate processing apparatus, it is said that the uniformity within the wafer surface and the reproducibility of the uniformity between the wafers are excellent. However, the single-wafer type substrate processing apparatus also includes a plurality of heating means in order to make the temperature distribution of the processing atmosphere uniform. That is, in order to further improve the uniformity within the wafer surface, it is essential to accurately reflect the interaction between temperature and film formation rate.

  The present invention has been proposed in view of the above-described conventional circumstances, and regardless of the operator, the appropriate set temperature of the heating means for realizing the desired temperature distribution in the processing chamber is uniquely determined in a short time. It is an object of the present invention to provide a substrate processing apparatus temperature control method, a substrate processing system, and a substrate processing apparatus that can be used.

  In order to achieve the above object, the present invention employs the following technical means. In the temperature control method for a substrate processing apparatus according to the present invention, a substrate accommodated in the processing chamber is processed in a state where the processing chamber is heated for each zone by a plurality of heating units that can be controlled independently of each other. First, substrate processing is performed with a detected temperature at a predetermined position corresponding to each heating means as a predetermined set temperature. Next, physical quantities that vary according to the processing temperature belonging to the substrate that has been subjected to the substrate processing are acquired at the measurement positions that are equal to or greater than the number of the heating means. Each measurement position is different from each other in the processing chamber. Subsequently, the deviation between the acquired physical quantity and the target value of the physical quantity is calculated for each measurement position. Further, when the set temperature corresponding to one heating means is changed, the amount of change of the physical quantity at each measurement position (hereinafter referred to as temperature change amount) changes the set temperature for each heating means. Obtained at. Then, based on the deviation at each measurement position and the temperature change amount at each measurement position, the correction amount of the set temperature of each heating means is calculated. In the subsequent substrate processing, a temperature obtained by adding the correction amount calculated as described above to the predetermined set temperature is set as a new set temperature. Here, for the physical quantity, a characteristic value that varies depending on the processing temperature, for example, a film thickness or deposition rate of a film deposited on the substrate, a resistance value of an impurity diffusion layer formed by ion implantation, or the like is used. be able to.

  According to this configuration, it is possible to determine the heat generation amount of each heating unit that realizes a desired processing atmosphere in consideration of the influence of the temperature change of each heating unit on each measurement position. Moreover, the set temperature of each heating means can be uniquely determined based on the operator's experience.

  The temperature control method can be applied to a batch type substrate processing apparatus in which a plurality of substrates are accommodated in a processing chamber. In this case, the measurement position is a substrate arranged at a different position in the processing chamber. As the physical quantity at each measurement position, an average value of the physical quantities obtained at a plurality of measurement points on the same substrate can be used. The temperature control method can also be applied to a single wafer processing apparatus in which a single substrate is accommodated in a processing chamber. In this case, the measurement position is a different point on the same substrate. In addition, it is preferable that at least one measurement position is set in a zone where each heating unit mainly performs heating.

で表現される行列式に基づいて演算することができる。ここで、ΔＭ_nはｎ番目の測定位置における上記偏差である。また、ΔＭ_nmはｍ番目の加熱手段に対応する設定温度のみを変化させたときのｎ番目の測定位置における単位温度あたりの上記温度変化量である。当該行列式は、ムーア-ペンローズ（Moore-Penrose）逆行列、または一般逆行列を用いることにより、設定温度補正量ΔＴ_mについて解くことができる。 When the number of the heating means is m and the number of the measurement positions is n (m ≦ n), the set temperature correction amount ΔT _m of the m-th heating means is

It can be calculated based on the determinant expressed by Here, ΔM _n is the deviation at the n-th measurement position. ΔM _nm is the temperature change amount per unit temperature at the nth measurement position when only the set temperature corresponding to the mth heating means is changed. The determinant can be solved for the set temperature correction amount ΔT _m by using a Moore-Penrose inverse matrix or a general inverse matrix.

  On the other hand, in another aspect, the present invention can provide a substrate processing system that realizes the above-described temperature control method. That is, the substrate processing system according to the present invention includes a substrate processing unit, a physical quantity acquisition unit, a deviation calculation unit, and a correction amount calculation unit. The substrate processing unit includes a processing chamber heated by a plurality of heating means arranged to be controllable independently of each other. In the substrate processing unit, the processing of the substrate accommodated in the processing chamber is performed in a state where the detected temperature at a predetermined position corresponding to each heating unit becomes a predetermined set temperature. Further, the physical quantity acquisition unit acquires a physical quantity that varies according to the processing temperature belonging to the substrate that has been subjected to the substrate processing. The physical quantity is acquired at measurement positions equal to or greater than the number of heating means. Here, the measurement positions are different from each other in the processing chamber. The deviation calculation unit calculates a deviation between the acquired physical quantity and the target value of the physical quantity for each measurement position. The correction amount calculation unit calculates the correction amount of the set temperature corresponding to each heating unit based on the deviation at each measurement position calculated by the deviation calculation unit and the temperature change amount acquired in advance at each measurement position. The correction amount calculation unit sets, in the substrate processing unit, a temperature obtained by adding the correction amount to the set temperature corresponding to each heating unit as a new set temperature for the subsequent substrate processing.

  The present invention can also provide a substrate processing apparatus that realizes the above-described temperature control method. That is, the substrate processing apparatus according to the present invention is arranged to be controllable independently of each other, and detects a plurality of heating means for heating a processing chamber in which the substrate is accommodated, and a temperature at a predetermined position corresponding to each heating means. And a plurality of temperature detecting means. A physical quantity that varies according to the processing temperature belonging to the substrate that has been subjected to the substrate processing in a state where each detected temperature becomes a predetermined set temperature is acquired at different measurement positions equal to or more than the number of heating means, and the acquired physical quantity The deviation of the physical quantity from the target value is calculated by the deviation calculation unit. Based on the deviation and a temperature change amount that is a change amount of the physical quantity at each measurement position when the set temperature corresponding to one heating means is acquired in advance at each measurement position. A calculation part calculates the correction amount of the set temperature corresponding to each heating means. In the subsequent substrate processing, the temperature control unit controls each heating unit using a temperature obtained by adding the correction amount to the set temperature corresponding to each heating unit as a new set temperature.

  According to the present invention, it is possible to determine the set temperature (heat generation amount) corresponding to each heating unit in consideration of the variation in the film forming rate of each heating zone due to the temperature change of the heating unit. For this reason, the processing position dependency of the processing state can be reduced. Further, since the processing time and the temperature correction amount of each heating means are also calculated based on the determinant, the set temperature of each heater can be uniquely determined without depending on the operator's experience.

(First embodiment)
Hereinafter, a substrate processing apparatus and a temperature control method according to a first embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the present invention is embodied as an example applied to the reduction of film formation variation in a vertical batch type low pressure CVD apparatus. FIG. 1 is a schematic sectional view showing a vertical vacuum CVD apparatus to which the present invention is applied.

  The low-pressure CVD apparatus 20 has a cylindrical metal flange 3 that is disposed on the cap 1 via an O-ring 2 and has an axis in the vertical direction. A gas introduction pipe 4 and an exhaust pipe 5 are connected to the side surface of the flange 3. The exhaust pipe 5 is connected to a vacuum pump 7 via a valve 6. A cylindrical quartz tube 13 having a vertical axis is disposed on the flange 3 via an O-ring 8. Only the lower end of the tube 13 is an open end, and the space sealed by the cap 1, the flange 3, and the tube 13 constitutes a processing chamber.

  A cylindrical inner tube 9 having an axial center in the vertical direction is accommodated between the flange 3 and the tube 13. Both ends of the inner tube 9 are open ends. A gas introduction pipe 10 is connected to the side surface of the inner tube 9 through the side surface of the flange 3. The source gas introduced into the inner tube 9 by the gas introduction pipe 10 is discharged from the upper end of the inner tube 9 to the exhaust pipe 5 via the space between the tube 13 and the inner tube 9. Substrates (wafers) to be processed are placed on the boat 12 at regular intervals in the vertical direction while maintaining the level. The boat 12 is accommodated in the inner tube 9 while being supported by the cap 1.

  A heater 11 (heating means) composed of a resistance heater or the like is disposed on the outer periphery of the tube 13. The heater 11 is composed of an annular heater divided into four along the vertical direction. Here, heaters 11 a, 11 b, 11 c, and 11 d are arranged in order from the upper side of the tube 13. Each of the heaters 11a to 11d is provided with a temperature sensor 14 (temperature detection means) made of a thermocouple or the like. In this embodiment, the temperature of each heater 11a, 11b, 11c, 11d is each directly detected by the corresponding temperature sensor 14a, 14b, 14c, 14d.

  When the wafer is set in the tube 13, the pressure in the tube 13 is reduced by the vacuum pump 7. At this time, the inside of the tube 13 is maintained at a constant temperature by the heating of the heater 11. In this state, a raw material gas is introduced into the tube 13 from the gas introduction tube 10 to deposit a film corresponding to the raw material gas on the wafer.

  FIG. 2 is a functional block diagram showing the configuration of the temperature control system of the low-pressure CVD apparatus of this embodiment. In FIG. 2, the same reference numerals are given to blocks corresponding to the members shown in FIG.

  As shown in FIG. 2, the temperature detected by the temperature sensor 14 is output to the temperature controller 24 as an electrical signal. The temperature control unit 24 controls the amount of heat generated by the heater 11 (11a to 11d) so that the temperature detected by the temperature sensor 14 (14a to 14d) matches the set temperature input via the input unit 21. Here, the temperature control unit 24 controls the amount of heat generated by the heater 11 by adjusting the amount of current to be supplied. When the temperature of each of the heaters 11a to 11d reaches the set temperature, the temperature control unit 24 notifies the film formation time control unit 25 and the gas supply unit 26, for example, by outputting a trigger signal. The film formation time control unit 25 starts measuring time in response to a signal from the temperature control unit 24, and the gas supply unit 26 responds to a signal from the temperature control unit 24 in the gas introduction pipe 10 (see FIG. 1). The raw material gas is supplied into the inner tube 9 through. When the film formation time set via the input unit 21 is reached, the film formation time control unit 25 instructs the gas supply unit 26 to stop supplying the source gas.

FIG. 3 is a flowchart showing processing of the temperature control method of the present embodiment. First, more than the number of monitoring wafers P of the heaters 11a to 11d are placed on the boat 12, and formation of a material film (film formation test) such as a silicon oxide film, a silicon nitride film, or a polysilicon film is performed (FIG. 3). S1). At this time, the number of monitoring wafers is equal to or greater than the number of heaters that can be controlled independently (here, four). The mounting position of the monitoring wafer is not particularly limited, but it is preferable that at least one monitoring wafer P is mounted in the heating zone corresponding to each of the heaters 11a to 11d. Here, as shown in the enlarged sectional view of the processing chamber of FIG. 4, five monitoring wafers P ₁ , P ₂ , P ₃ , P ₄ , P ₅ are placed on the boat 12 in order from the top at equal intervals. Yes. A wafer (dummy wafer) is placed between the monitoring wafers P _{1 to} P ₅ in order to realize the same processing environment as the actual product manufacturing process.

The temperature and film formation time set for each of the heaters 11a to 11d during the film formation may be the temperature and film formation time expected to form a film with a predetermined target film thickness. Such temperature and film formation time can be set, for example, by existing process data. Here, set temperatures T ₁ , T ₂ , T ₃ , and T ₄ for the heaters 11 a, 11 b, 11 c, and 11 d are set in the temperature control unit 24. Further, a film formation time t is set in the film formation time control unit 25. The set temperatures T _{1 to} T ₄ and the film formation time t are also stored in the storage unit 22 including a memory, an HDD (Hard Disk Drive), and the like.

When film formation is completed, each of the monitoring wafers P _{1 to} P ₅ is transferred to a film thickness measuring device 30 such as a spectroscopic ellipsometer, and the film thickness of the formed film is measured. The film thickness of each monitoring wafer P ₁ to P ₅ that is measured, the information identifying each monitoring wafer P ₁ to P ₅ (e.g., a wafer number) automatically or manually via the input unit 21 to the low pressure CVD device 20 with The data is input and stored in the storage unit 22. In the film thickness measurement of each of the monitoring wafers P _{1 to} P ₅ , it is preferable to measure the film thickness at a plurality of points in order to absorb film thickness variations in the wafer surface. In this case, the average film thickness is input to the reduced pressure CVD apparatus 20 as the film thickness of the monitoring wafers P _{1 to} P ₅ .

When the film thicknesses of the monitoring wafers P _{1 to} P ₅ are input, the deviation calculation unit 232 of the correction set temperature calculation unit 23 calculates the film formation time t and the film thicknesses of the monitoring wafers P _{1 to} P ₅ from the storage unit 22. read, calculates the deposition rate M ₁ ~M ₅ of each monitoring wafer P ₁ to P ₅ (FIG. 3 S2). The deviation calculator 232 calculates an average film formation rate M _all based on the calculated film formation rates M _{1 to} M ₅ of the respective monitoring wafers P _{1 to} P ₅ . Then, changes ΔM _{1 to} ΔM ₅ (hereinafter, deviations ΔM _{1 to} ΔM ₅ ) necessary for making the film formation rates of the monitoring wafers P _{1 to} P ₅ coincide with the average film formation rate are calculated (S 3 in FIG. 3). ).

FIG. 5 is a schematic diagram showing deviations of the respective monitoring wafers P _{1 to} P ₅ . In FIG. 5, the vertical axis corresponds to the film formation rate, and the horizontal axis corresponds to the monitoring wafers P _{1 to} P ₅ . In FIG. 5, the average film formation rate M _all is indicated by a broken line. As shown in FIG. 5, the deviations ΔM _{1 to} ΔM ₅ are differences between the film formation rates M _{1 to} M ₅ and the average film thickness rate M _all of the monitoring wafers P _{1 to} P ₅ . In this case, deviations ΔM _{1 to} ΔM ₅ are expressed by the following equations (1) to (6).

When deviation ΔM ₁ ~ΔM ₅ in each monitoring wafer P ₁ to P ₅ are calculated, the correction amount calculation unit 231 of the modified setting temperature calculation unit 23, a temperature correction amount ΔT ₁ ~ΔT ₄ for each heater 11a~11d Calculate.

In the temperature control method of this embodiment, the film formation rate change amount per unit temperature is used for the calculation of the temperature correction amounts ΔT _{1 to} ΔT ₄ . A film formation rate change amount per unit temperature (hereinafter referred to as a film formation rate temperature change amount) is acquired in advance prior to the calculation of the temperature correction amount (S4 in FIG. 3). Here, the film formation rate temperature change amount is, for example, when the set temperatures of the heaters 11a to 11d are T ₁ , T ₂ , T ₃ , and T ₄ (hereinafter referred to as the reference state), respectively. This is the amount of change in the film formation rate on each monitoring wafer when the set temperatures of ˜11d are changed by 1 ° C., respectively. Hereinafter, the film formation rate temperature variation of each of the heaters 11a to 11d is expressed as ΔM _nm . Here, n is the order when the highest-level monitoring wafer is first (n = 1 to 5), and m is the order when the highest-order heater is first (m = 1 to 4).

For example, when the set temperature of the heater 11a is changed by ΔT _a ° C., the amount of change in the film formation rate on the monitoring wafer P ₁ is ΔM ₁₁ × ΔT _a . Further, when the set temperature of the heater 11b is changed by ΔT _b ° C., the amount of change in the film formation rate on the monitoring wafer P ₁ is ΔM ₁₂ × ΔT _b . Further, when the set temperature of the heater 11c is changed by ΔT _c ° C, the amount of change in the film forming rate on the monitoring wafer P ₁ is ΔM ₁₃ × ΔT _c . When the set temperature of the heater 11d is changed by ΔT _d ° C, the amount of change in the film formation rate on the monitoring wafer P ₁ is ΔM ₁₄ × ΔT _d . Thus, the set temperature of the heater 11a [Delta] T _a ° C., the set temperature of the heater 11b [Delta] T _b ° C., the set temperature of the heater 11c T _c ° C., when the set temperature of the heater 11d [Delta] T _d ° C., simultaneously varied, monitoring wafer The film formation rate change amount Δm _{1 at} P ₁ is expressed by the following equation (7).

Therefore, a relational expression shown in the following expression (8) is established between the deviation ΔM ₁ and the temperature correction amounts ΔT _{1 to} ΔT ₄ .

Similarly, the following relational expressions (9) to (12) are established between the deviations ΔM ₂ , ΔM ₃ , ΔM ₄ , and ΔM ₅ and the temperature correction amounts ΔT _{1 to} ΔT ₄ .

From Expressions (8) to (12), the matrix shown in the following Expression (13) is between the deviations ΔM _{1 to} ΔM ₅ , the film formation rate temperature change amount ΔM _nm , and the temperature correction amounts ΔT _{1 to} ΔT _4. The formula holds.

The film formation rate temperature change amount ΔM _nm is a film formation rate change amount per unit temperature, and can be obtained as follows. The film formation rate temperature change amount ΔM _nm for the heater 11a is the film formation rate of each of the monitoring wafers P _{1 to} P ₅ when the set temperatures of the heaters 11a to 11d are T ₁ +1, T ₂ , T ₃ and T _4. And the difference between each film formation rate in the reference state. Further, the film formation rate temperature change amount for the heater 11b is the film formation rate of each monitoring wafer when the set temperatures of the heaters 11a to 11d are T ₁ , T ₂ +1, T ₃ , T ₄ , and the reference state. It is obtained from the difference from the film formation rate. Similarly, if the film formation rate temperature change to the heater 11c was the set temperature of each heater 11a~11d and _{T 1, T 2, T 3} + 1, T 4, also, the film formation rate temperature change amount to the heater 11d is is determined by the difference between the deposition rate in the deposition rate and the reference state of each monitoring wafer when the set temperature of each heater 11a~11d was _{T 1, T 2, T 3} , T 4 +1. The film formation rate temperature change amount ΔM _nm may be acquired in advance prior to the calculation of the temperature correction amounts ΔT _{1 to} ΔT ₄ , and the order is not limited to the order shown in FIG. In the present embodiment, the film formation rate temperature change amount ΔM _nm acquired as described above is input to the reduced pressure CVD apparatus 20 via the input unit 21 and stored in the storage unit 22.

When the deviation calculation unit 232 calculates the deviations ΔM ₁ to ΔM ₅ as described above, the deviation calculation unit 232 outputs the deviations ΔM _{1 to} ΔM ₅ to the correction amount calculation unit 231. The correction amount calculation unit 231 uses the deviations ΔM _{1 to} ΔM ₅ and the film formation rate temperature change amount ΔM _nm stored in the storage unit 22 to convert the determinant expressed by the above equation (13) into ΔT ₁ to ΔT. Solve for ₄ . Thereby, temperature correction amounts ΔT _{1 to} ΔT ₄ for the heaters 11a to 11d are obtained (S5 in FIG. 3).

となる。 In general, when a determinant expressed by B = AC is solved for C, an inverse matrix is used. That is,

It becomes.

  In the present embodiment, the matrices A, B, and C shown in the equation (14) are as shown in the following equations (15) to (17).

In this embodiment, since the matrix A is a 5 × 4 rectangular matrix, there is no general inverse matrix. For this reason, an unambiguous solution of equation (13) cannot be obtained. Therefore, in this embodiment, in order to obtain the most approximate solution using the concept of the space of the matrix, the Moore-Penrose inverse matrix A ⁺ that can obtain the solution having the minimum distance in the norm space is obtained. Used (reference: morphological analysis by Hirohiko Hanya, Kenichi Kawaguchi Baifukan (1991)). In this case, the expression (14) is expressed as the following expression (18).

  Each element of the Moore-Penrose inverse matrix can be calculated by a well-known algorithm used in commercially available software.

As described above, the correction amount calculation unit 231 calculates the temperature correction amounts ΔT _{1 to} ΔT ₄ for the respective monitoring wafers P _{1 to} P _5, and outputs the temperature correction amounts ΔT _{1 to} ΔT ₄ to the temperature control unit 24. . Thus the temperature control unit 24 performs subsequent deposition by adding the temperature correction amount ΔT ₁ ~ΔT ₄ corresponding to the set temperature T ₁ through T ₄ of each heater 11 a to 11 d (FIG. 3 S6). That is, the setting temperature of the heater 11a is changed from T ₁ to T ₁ + ΔT _1. The setting temperature of the heater 11b is changed from T ₂ to T ₂ + ΔT _2. Similarly, the set temperature of the heater 11c is changed from T ₃ to T ₃ + [Delta] T _3, the set temperature of the heater 11d is changed from T ₄ to T ₄ + ΔT _4.

Further, the correction amount calculation unit 231 calculates the film formation time t ^′ during the subsequent film formation process based on the film formation rate on each of the monitoring wafers P _{1 to} P ₅ after the temperature correction. When the target film thickness is X (nm), it is considered that the film formation time t ^′ is the average film formation rate M _all for all the monitoring wafers P _{1 to} P ₅ , and t ^′ = X / M _all can be obtained. However, since the above-described temperature correction amounts ΔT _{1 to} ΔT ₄ are obtained by arithmetic calculation, they are calculated up to a numerical value equal to or less than the minimum unit that can be set in the heaters 11a to 11d. For this reason, strictly speaking, the film formation rate at the positions of the respective monitoring wafers P _{1 to} P ₅ cannot be set to the average film formation rate M _all . For this reason, in the present embodiment, the corrected set temperature calculation unit 23 sets ΔT ₁ to ΔT ₄ in a temperature that can be actually set by the temperature control unit 24, that is, a minimum unit that can be set by the temperature control unit 24. . In this case, the corrected set temperature calculating unit 23 substitutes the temperature correction amounts ΔT _{1 to} ΔT ₄ actually set in the temperature control unit 24 into the equation (13), thereby forming the film on each of the monitoring wafers P _{1 to} P ₅ . determine the rate M ^{_'1 ~M'} _5. Then, the correction amount calculation unit 231 obtains the film formation time t ^′ from the following equation (19), and sets the film formation time t ^′ in the film formation time control unit 25.

  Thereby, the low-pressure CVD apparatus 20 can form a film that is close to the target film thickness and has a very small film thickness distribution between wafers in the same batch in the subsequent film formation.

  The modified set temperature calculation unit 23, the temperature control unit 24, and the film formation time control unit 25 included in the low-pressure CVD apparatus 20 of the present embodiment include, for example, a dedicated calculation circuit, a processor, a memory such as a RAM, a ROM, and the like. And hardware that is stored in the memory and software that operates on the processor.

  As described above, according to the present embodiment, in the batch type low pressure CVD apparatus, the dependency of the film thickness formed on the wafer on the wafer placement position can be reduced. In the present embodiment, the set temperature of each heater can be obtained by a single film formation test regardless of the experience of the operator. For this reason, the heater set temperature can be optimized in a very short time.

  Furthermore, since the set temperature of the heater can be adjusted to the minimum settable unit, more precise conditions can be obtained compared to the conventional case. As a result, the capacity of the facility can be maximized, and it is possible to cope with the thinning and the improvement of film thickness uniformity, which are becoming increasingly demanding as the element pattern becomes finer.

  For example, in the deposition of a silicon oxide film using TEOS (Tetra Ethyl 0rtho Silicate) as a raw material, the film thickness uniformity within the same batch is improved by about 8% by applying the above temperature control method. . As described above, by stabilizing the silicon oxide film thickness, a side made of a silicon oxide film, a silicon nitride film, or the like that determines the lateral length of a so-called LDD (Lightly Doped Drain) region of a MOS (Metal Oxide Semiconductor) transistor. Wall dimensions can be stabilized. As a result, the threshold voltage Vt of the MOS transistor can be stabilized, and a semiconductor device with small characteristic variations can be stably produced.

By the way, although the case where there are four heaters and five monitoring wafers has been described above, the above-described content has m heaters and n monitoring wafers P _n (m ≦ n). It can also be applied to a low-pressure CVD apparatus using In this case, the deviation ΔM _n of the film formation rate for each of the n monitoring wafers and the temperature correction amount ΔT _m of each of the m heaters are a matrix shown in the equation (20) using the film formation rate temperature change ΔM _nm. Satisfies the equation.

  In this case, the matrices A, B, and C in the equation (14) are as shown in the following equations (21) to (23).

Accordingly, by solving the determinant shown in the equation (20) for ΔT ₁ to ΔT _m using the Moore-Penrose inverse matrix A ⁺ of the matrix A, _m monitoring wafers P _n each having the target physical quantity are obtained. The set temperature correction amount of each heater can be obtained. When the matrix A is a square matrix (n = m), the determinant shown in Expression (20) can be solved using the general inverse matrix A ⁻¹ of the matrix A. In this case, the film formation time t ^′ can be obtained by using the following formula (24) based on the film formation rates M ^′ _{1 to} M ^′ _n of the respective monitoring wafers P _{1 to} P _n .

(Second Embodiment)
In the first embodiment, an example in which the present invention is applied to a batch type low pressure CVD apparatus has been described. However, the present invention can also be applied to a single wafer type substrate processing apparatus. In the present embodiment, the present invention is embodied as an example applied to the reduction of film formation variation in a single wafer type low pressure CVD apparatus. FIG. 6 is a schematic diagram of a single wafer type low pressure CVD apparatus to which the present invention is applied.

  The reduced-pressure CVD apparatus 50 includes a chamber (processing chamber) 15 formed so that gas can be introduced in a state where the pressure is reduced compared to the external environment (atmospheric pressure). The wafer 18 is placed on a point support 17 provided in the chamber 15. Although not shown, a gas introduction pipe and an exhaust pipe are connected to the chamber 15 in the same manner as the low-pressure CVD apparatus described in the first embodiment. In the low pressure CVD apparatus 20, a heater 16 made of, for example, a resistance heater or a lamp is provided facing the wafer 18. In the present embodiment, the heater 16 includes four heaters 16a to 16d that can be controlled independently of each other. As in the first embodiment, the amount of heat generated by each heater 16a to 16d is adjusted so that the detected temperature of the temperature sensors 19a to 19d including thermocouples provided in the heaters 16a to 16d reaches a predetermined temperature. .

  When the wafer 18 is set in the chamber 15, the pressure in the chamber 15 is reduced. At this time, the inside of the chamber 15 is maintained at a constant temperature by the heating of the heater 16. In this state, a raw material gas is introduced into the chamber 15 from the gas introduction pipe, whereby a film corresponding to the raw material gas is deposited on the wafer 18.

In this embodiment, since the wafers are processed one by one, the monitor position P corresponding to the monitoring wafer of the first embodiment is set on the same wafer. FIG. 7 is a plan view showing the positional relationship between the monitor position P and the heater 16 of the single wafer type low pressure CVD apparatus 50. As shown in FIG. 7, in this embodiment, the monitor position P ₁ is set at the center of the wafer 18 as the monitor position P, and the monitor positions P _{2 to} P ₅ are set at the peripheral edge of the wafer 18. As in the first embodiment, the monitor position may be equal to or greater than the number of heaters 16 (four here). Each monitor position P is preferably set to at least one monitor position P in the heating zone corresponding to each heater 16a to 16d. Here, the monitor position P ₂ to P ₅ are disposed respectively in the heating zone of the heater 16 a to 16 d.

  FIG. 8 is a functional block diagram showing a CIM (Computer Integrated Manufacturing) system in which the above-described reduced-pressure CVD apparatus 50 is incorporated. In the CIM system, various manufacturing apparatuses and inspection apparatuses used in the semiconductor device manufacturing process are connected to the CIM server 41 via a network or the like. The CIM server 41 realizes stable production of the semiconductor device by, for example, finely adjusting the manufacturing conditions in the manufacturing apparatus based on the production management of the manufacturing apparatus and the inspection result acquired by the inspection apparatus. For example, in the film forming process, the film thickness of the film formed by the film thickness measuring device 30 such as a spectroscopic ellipsometer after the film formation is measured. The measurement result is transmitted to the CIM server 41 together with a number for identifying the wafer and stored in the CIM server 41. Based on the inspection result of the film thickness measuring device 30, the CIM server 41 instructs the low-pressure CVD device 50 on the set temperature and film formation time of each heater.

  The CIM system of this embodiment includes a corrected set temperature calculation device 42. The corrected set temperature calculation device 42 includes a correction amount calculation unit 421 and a deviation calculation unit 422. Hereinafter, a procedure for optimizing the set temperatures of the heaters 16a to 16d in the system will be described.

Also in the present system, as in the first embodiment, first, the wafer 18 is set in the chamber 15 of the low-pressure CVD apparatus 50 to form a film such as a silicon oxide film, a silicon nitride film, or a polysilicon film (film formation). Test). The temperature and film formation time set for each of the heaters 16a to 16d during the film formation are set to a temperature and a film formation time at which film formation with a predetermined target film thickness is expected. Here, an instruction that the set temperatures of the heaters 16a, 16b, 16c, and 16d are temperatures T ₁ , T ₂ , T ₃ , and T ₄ and the film formation time is time t is sent from the CIM server 41 to the low-pressure CVD apparatus 50. Given. The low-pressure CVD apparatus 50 includes the temperature control unit and the film formation time control unit described in the first embodiment, and executes film formation according to the set temperature and film formation time input from the CIM server 41. The temperature and the film formation time are stored in the CIM server 41 as a process history.

When the film formation is completed, the wafer 18 is transferred to the film thickness measuring device 30. The film thickness measuring device 30 measures the film thickness at each of the film thickness monitor positions P _{1 to} P ₅ illustrated in FIG. 7 based on the coordinate information on the wafer 18 instructed from the CIM server 41. The film thickness at each of the monitor positions P _{1 to} P ₅ is transmitted to the CIM server 41 together with the coordinate information and stored in the CIM server 41.

Next, the CIM server 41 transmits the film thickness and position information of each of the monitor positions P _{1 to} P ₅ , the set temperature and the film formation time of each of the heaters 16 a to 16 d to the corrected set temperature calculation device 42. Deviation calculation unit 422, based on the film thickness and the deposition time of each monitoring position P ₁ to P ₅ received, to calculate the deposition rate M ₁ ~M ₅ at each monitoring location P ₁ to P _5, An average film formation rate M _all at each of the monitor positions P _{1 to} P ₅ is calculated. Then, deviations ΔM _{1 to} ΔM ₅ for making the film formation rates at the monitor positions P _{1 to} P ₅ coincide with the average film formation rate are calculated based on the above formulas (1) to (6).

When the deviations ΔM _{1 to} ΔM _{5 at the} respective monitor positions are calculated, the correction amount calculation unit 421 solves the determinant shown in the above equation (13) with respect to the temperature correction amounts ΔT _{1 to} ΔT ₄ to thereby obtain the heaters 16a. The temperature correction amounts ΔT _{1 to} ΔT ₄ for ˜16d are calculated. Here, it is assumed that the correction amount calculation unit 421 stores the film formation rate temperature change amount ΔM _nm at each of the monitor positions P _{1 to} P ₅ acquired in advance by the method described in the first embodiment. Also in this embodiment, the matrix A is a 5 × 4 rectangular matrix. For this reason, when solving the determinant shown in the above equation (13), the correction amount calculation unit 421 uses the Moore-Penrose inverse matrix.

As described above, when the temperature correction amounts ΔT _{1 to} ΔT ₄ at the respective monitor positions P _{1 to} P ₅ are calculated, the correction amount calculation unit 421 sets the previous set temperatures T _{1 to} T ₄ of the heaters 16a to 16d. A new set temperature obtained by adding the temperature correction amounts ΔT _{1 to} ΔT ₄ is output to the reduced pressure CVD film forming apparatus 50. Thereby low pressure CVD film forming device 50 changes the set temperature of the heater 16a to T ₁ + ΔT ₁ from T ₁ to change the set temperature of the heater 16b from T ₂ to T ₂ + ΔT _2, the set temperature of the heater 11c changed from T ₃ to T ₃ + ΔT _3, by changing the set temperature of the heater 11d from T ₄ to T ₄ + ΔT _4, to implement the subsequent deposition.

Further, the correction amount calculation unit 421 calculates the film formation time t ^′ during the subsequent film formation process based on the above equation (19), and outputs it to the low pressure CVD film formation apparatus 50. Thereby, the low-pressure CVD apparatus 50 can form a film that is close to the target film thickness and has a very small film thickness distribution in the wafer surface in the subsequent film formation.

  As described above, according to the present embodiment, in the single wafer type low pressure CVD apparatus, it is possible to reduce the in-wafer variation of the film thickness formed on the wafer, and the same as in the first embodiment. An effect can be obtained.

  The modified set temperature calculation device 42 included in the CIM system of the present embodiment includes, for example, a dedicated calculation circuit, hardware including a processor and a memory such as a RAM and a ROM, and the memory stored in the memory. It can be realized as software operating on the above. In the above description, the CIM server 41 and the corrected set temperature calculation device 42 are described as separate devices. However, the function of the correction set temperature calculation device 42 may be realized by the CIM server 41.

  As described above, according to the present invention, an appropriate set temperature of the heating means for realizing a desired temperature distribution in the processing chamber can be uniquely determined in a short time regardless of the operator.

  The above-described embodiments do not limit the technical scope of the present invention, and various modifications and applications other than those already described are possible within the scope of the present invention. For example, in the above description, the film formation rate is used as a physical quantity belonging to the wafer to be processed, which varies depending on the processing temperature. However, the film thickness can be used as the physical quantity. Further, the present invention is not limited to a low pressure CVD apparatus and can be applied to all substrate processing apparatuses that perform substrate processing in a heated atmosphere. For example, the present invention can be applied to a heat treatment apparatus that performs dry oxidation, wet oxidation, oxidation by RTA (Rapid Thermal Annealing), or the like. In this case, the thickness of the oxide film and the film formation rate can be used as physical quantities. When applied to a heat treatment apparatus that activates an impurity diffusion layer formed by ion implantation, the resistance value or the like of the impurity diffusion layer can be used as a physical quantity. Further, the target value of the physical quantity is not limited to the average value of the deviation, and an arbitrary value can be set.

  Further, in each of the above embodiments, the heating amount of each heating unit is adjusted by detecting the temperature of each heating unit. However, the detected temperature is the temperature of the outer wall of the processing chamber facing the heating unit, etc. Any temperature at a predetermined position corresponding to each heating means may be used.

  According to the present invention, it is possible to uniquely determine an appropriate set temperature of a heating unit that realizes a desired temperature distribution in a processing chamber in a short time, a temperature control method for a substrate processing apparatus, a substrate processing system, and It is useful as a substrate processing apparatus.

Schematic sectional view of a batch type low pressure CVD apparatus to which the present invention is applied Schematic functional block diagram of a low pressure CVD apparatus in the first embodiment of the present invention The flowchart which shows the temperature control method in the 1st Embodiment of this invention. Schematic cross-sectional view showing the processing chamber of a batch-type reduced-pressure CVD apparatus in an enlarged manner Schematic diagram showing the deviation Schematic of single wafer type low pressure CVD apparatus to which the present invention is applied Schematic diagram showing heating zone and film thickness monitor position of single-wafer vacuum CVD equipment Schematic functional block diagram of the CIM system in the second embodiment of the present invention

Explanation of symbols

5 Exhaust pipe 9 Inner tube 10 Gas introduction pipe 11 Heater (heating means)
12 Boat 13 Tube (Processing room)
14 Temperature sensor (temperature detection means)
15 Chamber (Processing chamber)
16 Heater (heating means)
19 Temperature sensor (temperature detection means)
20 Low-pressure CVD device 23 Correction set temperature calculation unit 24 Temperature control unit 25 Deposition time control unit 30 Film thickness measurement device 41 CIM server 42 Correction set temperature calculation devices 231 and 421 Correction amount calculation units 232 and 422 Deviation calculation unit

Claims (13)

A temperature control method for a substrate processing apparatus for processing a substrate housed in the processing chamber in a state where the processing chamber is heated for each zone by a plurality of heating means that can be controlled independently of each other,
Performing substrate processing with a detection temperature at a predetermined position corresponding to each heating means as a predetermined set temperature;
Obtaining physical quantities that vary according to the processing temperature belonging to the substrate that has undergone the substrate processing, at different measurement positions in the processing chamber, and at more measurement positions than the number of heating means;
Calculating a deviation between the acquired physical quantity and a target value of the physical quantity for each measurement position;
Obtaining a temperature change amount, which is a change amount of the physical quantity at each measurement position when the set temperature corresponding to one heating means is changed, by changing the set temperature for each heating means; and
Calculating a correction amount of the set temperature corresponding to each heating means based on the deviation at each measurement position and the temperature change amount at each measurement position;
Performing the subsequent substrate processing as a new set temperature, the temperature obtained by adding the correction amount to the set temperature corresponding to each heating means;
A temperature control method for a substrate processing apparatus, comprising:   The temperature control method for a substrate processing apparatus according to claim 1, wherein a plurality of substrates are accommodated in the processing chamber, and different substrates are set as the measurement positions.   The temperature control method for a substrate processing apparatus according to claim 2, wherein the physical quantity at the measurement position is calculated based on physical quantities acquired at a plurality of points on the same substrate.   The temperature control method for a substrate processing apparatus according to claim 1, wherein a single substrate is accommodated in the processing chamber, and a different point on the same substrate is set as the measurement position.   2. The temperature control method for a substrate processing apparatus according to claim 1, wherein at least one of the measurement positions is set in a zone in which each heating means mainly performs heating. When the number of the heating means is m and the number of measurement positions is n (m ≦ n), the correction amount ΔT _m corresponding to the m-th heating means is equal to the correction amount ΔT _m at the n-th measurement position. By the deviation ΔM _n and the temperature change amount ΔM _nm per unit temperature at the n-th measurement position when the set temperature corresponding to the m-th heating means is changed,

The temperature control method for a substrate processing apparatus according to claim 1, wherein the temperature control method is calculated based on a determinant expressed by: The temperature control method for a substrate processing apparatus according to claim 6, wherein the set temperature correction amount ΔT _m is calculated using a Moore-Penrose inverse matrix or a general inverse matrix.   The temperature control method for a substrate processing apparatus according to claim 1, wherein the physical quantity is a film formation rate of a film formed on the substrate. In a substrate processing system that processes substrates in a heated atmosphere,
A processing chamber in which the substrate is accommodated, a plurality of heating means arranged to be controllable independently of each other, and a means for detecting a temperature at a predetermined position corresponding to each of the heating means. Means for performing substrate processing at a set temperature of
Means for acquiring a physical quantity belonging to a substrate that has been subjected to substrate processing and that varies depending on a processing temperature;
Means for calculating, for each measurement position, a deviation between the physical quantity acquired at the measurement position equal to or greater than the number of the heating means and a target value of the physical quantity at different positions in the processing chamber;
The deviation at each measurement position and the temperature change amount that is the change amount of the physical quantity at each measurement position when the set temperature corresponding to one heating means is acquired in advance at each measurement position. A means for calculating a correction amount of the set temperature corresponding to each heating means,
Means for setting a temperature obtained by adding the correction amount to a set temperature corresponding to each heating means as a new set temperature in the substrate processing means;
A substrate processing system comprising:   The substrate processing system according to claim 9, wherein at least one measurement position is set in a zone where each heating unit mainly performs heating.   The substrate processing system according to claim 9, wherein the physical quantity is a film formation rate of a film thickness of a film formed on the substrate. In a substrate processing apparatus for processing a substrate accommodated in a processing chamber in a heated atmosphere,
A plurality of heating means arranged to be controllable independently of each other and heating the processing chamber;
A plurality of temperature detecting means for detecting a temperature at a predetermined position corresponding to each heating means;
Varying according to the processing temperature belonging to the substrate that has been subjected to the substrate processing in a state where each detection temperature becomes a predetermined set temperature at different measurement positions in the processing chamber and at more than the number of the heating means. Means for calculating a deviation between the physical quantity and a target value of the physical quantity;
The deviation at each measurement position and the temperature change amount that is the change amount of the physical quantity at each measurement position when the set temperature corresponding to one heating means is acquired in advance at each measurement position. A means for calculating a correction amount of the set temperature corresponding to each heating means,
In the subsequent substrate processing, a means for controlling each heating means with a temperature obtained by adding the correction amount to a set temperature corresponding to each heating means as a new set temperature;
A substrate processing apparatus comprising: The substrate processing apparatus according to claim 12, wherein the physical quantity is a film formation rate of a film thickness formed on the substrate.

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